Conventionally, a server transmits data to a terminal at a predetermined transmission rate in performing a video data streaming service through a network.
Accordingly, when there occurs a network congestion due to an instantaneous increase in the number of users concurrently accessing the network, e.g., a wireless network, through which a video data streaming service is provided, or when a mobile terminal of a user is in a shadow zone, where the quality of the wireless network is deteriorated, video data being reproduced in the user's terminal malt be broken-off or be delayed,